CN110431316B

CN110431316B - Method for controlling a hydraulic actuating drive, control device and actuating drive controller

Info

Publication number: CN110431316B
Application number: CN201880016040.1A
Authority: CN
Inventors: C.奥尔特纳; F.霍夫曼
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2017-03-06
Filing date: 2018-02-22
Publication date: 2021-02-09
Anticipated expiration: 2038-02-22
Also published as: US20190383310A1; WO2018162243A1; EP3592991A1; DE102017106840A1; EP3592991B1; CN110431316A

Abstract

The invention relates to a method for controlling a hydraulic actuating drive having an actuator, the position of which is adjusted by means of at least one electrohydraulic proportional valve having at least one electrical input and at least one hydraulic output, comprising the following steps: -acquiring a position of the actuator and generating a position actual value depending on the acquired position; the position setpoint value is preset as a function of a preset for a desired position of the actuator, and the setpoint/actual value difference is set using at least one electrohydraulic proportional valve, so that the actuator assumes a position corresponding to the position setpoint value. The method according to the invention is characterized in that the position setpoint value is changed even without a preset change for the desired position of the actuator.

Description

Method for controlling a hydraulic actuating drive, control device and actuating drive controller

The present invention relates to a method for controlling a hydraulic actuator, to a control device for controlling at least one proportional valve for controlling a hydraulic actuator, comprising an actuator, and to an actuator control, in particular according to the preambles of the independent claims.

Actuator controls are known, for example, in the form of directional slide valve modules. In known directional control valve modules of this type, as shown in fig. 1, two directional control valves are redundantly arranged to generate a hydraulic supply pressure for an actuating drive, for example an actuating cylinder, in order to apply the hydraulic supply pressure to the actuating drive, so that the actuating drive or its actuator is moved as a function of the hydraulic supply pressure. The actuating drive, in turn, may move a valve, which controls the mass flow for supplying the engine or the work machine, for example. With such a directional slide valve module, the mass flow can be regulated very precisely and highly dynamically.

Referring to fig. 1, a known directional control valve module for controlling a hydraulic actuating drive 1 having an actuator 1.1 has two redundantly arranged directional control valves 2, 3. In fig. 1, the directional spool valve module is schematically defined by a dashed line.

Each direction slide valve 2, 3 is embodied as an electrohydraulic proportional valve having an

electrical input

4, 5 and a

hydraulic output

6, 7. A signal or current is supplied to the respective

electrical input

4, 5, which signal or current determines the position of the respective directional control valve 2, 3 and thus the hydraulic pressure output by this directional control valve at the

hydraulic output

6, 7. In the embodiment shown in fig. 1 and also in the embodiment of the invention, each directional control valve 2, 3, in conjunction with the actuator 1, converts a constant or hydraulic input pressure, which is applied to the respective pressure input 25 and is generated, for example, by means of a pump 26 which is driven by a hydraulic tank 27, into a variable control stroke. The signal applied to the

electrical inputs

4, 5 or the corresponding current intensity, for example, between 4 and 20mA, is preset for adjusting the stroke of the drive 1 or its actuator 1.1.

The two directional control valves 2, 3 are connected together via a common hydraulic pressure selection device 8 for controlling the actuating drive 1 with a common input pressure. Via the pressure selection device 8, the pressure at the hydraulic outputs 6 and/or 7 of the two directional control valves 2, 3 is supplied to the hydraulic actuating drive 1, so that the actuator 1.1 of the hydraulic actuating drive assumes a specific position or executes a specific stroke depending on the supplied hydraulic pressure. Depending on the stroke, the valve 28, which regulates the mass flow for supplying the engine or the work machine, in this case for example a steam turbine 29, is opened to a greater or lesser extent.

Each of the directional control valves 2, 3 comprises an electronic monitoring circuit which identifies a fault situation of the directional control valve 2, 3. In the event of a fault, the hydraulic pressure selection device 8 ensures that the other directional control valves 2, 3 assume this function. Thus, fault situations can be eliminated during operation and the directional slide valves 2, 3 can even be replaced during operation. Thus, the redundancy of the directional slide valves 2, 3 improves the operational safety and availability of the directional slide valve module and reduces the downtime of the connected engine or work machine.

For each directional slide 2, 3, a position detection device 11, 12 is provided, which detects the position of the actuator 1.1 of the actuating drive 1 and informs the

position controller

14, 15 provided in the respective directional slide 2, 3 of the respective actual position value.

The position setpoint for each directional slide 2, 3 is preset by the pilot system 30 and is likewise supplied to the

respective position controller

14, 15. Accordingly, a

position setpoint input

9, 10 is provided for each directional slide 2, 3, and a

position controller

14, 15 controls the setpoint/actual value difference in order to set the actuator 1.1 of the drive 1 to a desired stroke or to assume a desired position.

In the embodiment shown, it is problematic that, in the event of a continuous operation, for example due to a failure of the position detection 11, 12, a pressure drop can occur when switching from the directional control valve 2 to the other directional control valve 3 or vice versa. Furthermore, it cannot easily be checked whether one of the two directional control valves 2, 3 is damaged or whether the respective other directional control valve 2, 3 can assume its function alone during the switching operation.

In the event of a failure of the respective position detection 11, 12, the associated directional control valves 2, 3 can no longer be operated even if they are still fully operational. Furthermore, there is the risk that particle deposits result in a limited range of motion of the actuating drive 1 in the hydraulic section, in particular in the case of long constant operating modes. In the extreme case, the valve 28 can no longer be closed.

In the event of a failure of the setpoint specification, the associated directional control valves 2, 3 can no longer be operated even if they are still fully operable.

The object of the present invention is therefore to provide a method for controlling a hydraulic actuating drive, which avoids at least one or more of the disadvantages mentioned above, starting from the known directional control valve module as an actuating drive control for controlling a hydraulic actuating drive. Furthermore, a corresponding control device and a control unit for the actuating drive are to be specified.

The object is achieved according to the invention by a method, a control device and a regulation drive controller according to the independent claims. Advantageous and particularly advantageous embodiments of the invention are specified in the dependent claims.

The method according to the invention for controlling a hydraulic actuating drive having an actuator, the position of which is adjusted by means of at least one electrohydraulic proportional valve having at least one electrical input and at least one hydraulic output, comprises the following steps:

-acquiring a position of the actuator and generating a position actual value corresponding to the acquired position;

-presetting a position setpoint value and regulating the setpoint/actual value difference with at least one electrohydraulic proportional valve, so that the actuator assumes a position corresponding to the position setpoint value; the position setpoint is preset in dependence on a preset for the desired position of the actuator, wherein the preset can be generated, for example, by the actuator or an external system (such as a turbine controller) to which the component operated by the actuator belongs when the valve of the turbine is operated by the actuator.

In the case of a constant setting for the desired position of the actuator, i.e. in particular by an external system, the position setpoint value is also changed according to the invention.

The at least one electrohydraulic proportional valve can be embodied, for example, as a directional spool valve. However, other embodiments are also conceivable in which the electrical signal is converted into a hydraulic signal or into a hydraulic pressure.

The hydraulic actuating drive has, for example, at least two electrohydraulic proportional valves, which each have at least one electrical input and at least one hydraulic output and whose hydraulic outputs are connected together for controlling the actuating drive with a common hydraulic input pressure. In this embodiment, in the case of a change in the position setpoint value of the setpoint value supplied to one of the electrohydraulic proportional valves (also referred to as a position setpoint actuation), the pressure change in the hydraulic output of this electrohydraulic proportional valve can be compensated by a change in the pressure in its hydraulic output regulated by at least one further electrohydraulic proportional valve, in order to keep the common hydraulic input pressure for the control drive constant. This means that although the position setpoint is also actuated according to the invention, an undesired change in the position of the actuator is at least to some extent precluded if a presetting is not actually necessary on account of the "external" setpoint. At the same time, the problem of the limited range of motion of the actuating drive indicated at the outset is avoided by the usually slight change in the position setpoint value, and the reaction time in the system is reduced, thereby ensuring a significantly smaller pressure drop.

According to an embodiment of the invention, the change in the position setpoint value can be carried out in the form of a regular or irregular superposition of vibrations on the setpoint value, which setpoint value is preset as a function of the presetting for the desired position of the actuator. The wavy or stepped curve is therefore modulated to the target value or a wavy or stepped curve "oscillating" around zero is added to the target value, whereby a long constant position of at least one electrohydraulic proportional valve or other components for controlling the actuating drive is avoided.

Alternatively, the change in the position setpoint value can also take place in the form of a separate amplification and/or reduction of the setpoint value, which is preset as a function of the preset for the desired position of the actuator. In this embodiment, the individual pulses are modulated or added to the setpoint value, in other words in the sense that the setpoint value can subsequently be set up or reduced again. In other words, a rating that is too large or too small is respectively preset for a short period of time before the "suitable" rating is set again.

According to an embodiment of the invention, in addition to the setpoint value changes shown, the function of the electrohydraulic proportional valve and in particular of the further components for control are also tested, i.e. the setpoint value supplied to the electrohydraulic proportional valve is in turn reduced in a targeted manner and the pressure in the respective hydraulic output is monitored for a corresponding change. In principle, it is also possible to carry out such a test by specifically increasing the setpoint value of the supply, and then to monitor whether the pressure in the respective hydraulic output is changing accordingly. In practice, however, a reduction has proven to be particularly advantageous.

In this test, the pressure reduction in the hydraulic output is preferably compensated by a regulated pressure increase in the further hydraulic output or, in the second embodiment mentioned, by a regulated pressure reduction in the further hydraulic output, in order to keep the common hydraulic input pressure for the actuator constant and thus also not undesirably influence the position of the actuator during the test.

Preferably, the pressures in the hydraulic outputs are again equalized with one another after compensation by changing the pressure in the further hydraulic outputs. This applies to the illustrated position setpoint value changes (also referred to as position setpoint manipulation) and/or to the mentioned tests.

According to an embodiment, the change of the position setpoint value and/or the implementation of the test can be stopped. In particular, if an inappropriate pressure in the respective hydraulic output of the respective electrohydraulic proportional valve is determined in the event of a change in the position setpoint value, the change in the position setpoint value is ended and only the preset use position setpoint value for the desired position of the actuator is also used. The corresponding situation applies to the test. In the event of an unreliable determined pressure in the hydraulic output, the test is no longer carried out and, in particular, an optical and/or acoustic warning and/or warning message is output.

Preferably, the position of the actuator is detected by two or three position detection devices, and a selection of 2-out-of-1, 3-out-of-1 or 3-out-of-2 is carried out from the position actual values generated by the position detection devices, wherein only one or more selected position actual values are taken into account for setting the setpoint/actual value difference or for changing the position setpoint value. It is also possible to form a mean value from the generated position actual values and to use the mean value for adjusting the setpoint/actual value difference or for changing the position setpoint value.

The control device according to the invention for controlling at least one electrohydraulic proportional valve has an input and an output for at least one position actual value and a position setpoint value for the position of the actuator and is designed for carrying out the method according to the invention, the electrohydraulic proportional valve in turn being designed for controlling a hydraulic control drive comprising the actuator.

The actuator control device according to the invention is designed for controlling a hydraulic actuator, for example for controlling a hydraulic cylinder. The actuator control device comprises at least two electrohydraulic proportional valves which are arranged redundantly for generating a hydraulic input pressure for the actuator. The redundant arrangement means that each electrohydraulic proportional valve is able to ensure the function of the actuator control unit individually, i.e. to provide hydraulic pressure for actuating the actuator.

Each electro-hydraulic proportional valve has at least one electrical input and at least one hydraulic output.

The hydraulic outputs of the at least two electrohydraulic proportional valves are connected together via a common hydraulic pressure selection device, in particular embodied as a maximum pressure selection device, for controlling the actuating drive with a common input pressure.

The actuator control has a position setpoint input for each electrohydraulic proportional valve, which is connected to the electrical input of the respective electrohydraulic proportional valve, so that the respective electrohydraulic proportional valve can be preset with a position setpoint.

At least one position detection device is provided for detecting the position of the actuator of the actuating drive, wherein the position detection device generates a position actual value.

Each electrohydraulic proportional valve comprises a position controller which is designed to control a setpoint/actual value difference using a position setpoint value from a position setpoint value input and a position actual value from a position detection device.

The control drive according to the invention has at least one electronic switching device, with which at least one position setpoint value from the position setpoint value input and/or a position actual value from the position detection device can be selectively replaced by a default value. The possibility of replacing the position setpoint value, which is preset in particular by an external system for the desired position of the actuator (by the system), enables the previously described setpoint value change or setpoint actuation, so that instead of the initial position setpoint value from the position setpoint input, the changed position setpoint value can be taken into account for controlling the actuator or for setting the setpoint/actual value difference.

Depending on the number of preset setpoint values, a selection of 2-from-1, 3-from-1 or 3-from-2 from the position setpoint values preset by the external system can be made and the respectively selected value or values can be used as the position setpoint value or values. Mean value formation and use of mean values are also possible.

According to one embodiment of the invention, the electronic switching device can be provided by software and, according to a further embodiment, by hardware. In a software solution, a software-implemented logic module is provided which replaces the position setpoint value and/or the position actual value by a preset value.

By means of the embodiment according to the invention, the two electrohydraulic proportional valves can still be operated even if the setpoint position value and/or the actual position value fails. Furthermore, a setpoint control is possible, which enables, in particular, also in continuous operation, the testing of the electrohydraulic proportional valve or the control drive. It can thus be checked, for example, whether the valve operated by the actuating drive can also be closed.

As explained, one or more electrohydraulic proportional valves may preferably be implemented as directional spool valves. Accordingly, a directional valve module can be installed as described above.

By means of the setpoint actuation or the setpoint value changes indicated, a pressure equalization can be produced in the directional control valve module, which minimizes the movement of the actuator of the actuating drive and the valve connected therewith in the event of a malfunction of the directional control valve. Thus, a relatively small pressure drop can be ensured. I.e. by continuously comparing the current pressure on the output of the directional slide valve and continuously readjusting, a fast response capability of the system is ensured.

The functionality of the two directional control valves can advantageously be checked, in particular even in continuous operation, by the previously shown continuous setpoint actuation/setpoint value change when simultaneously measuring the associated pressure, in particular at the respective hydraulic outputs of the directional control valves. In a similar manner to the usual representation for any implemented electrohydraulic proportional valve, the setpoint value of the first directional control slide is advantageously also reduced, the pressure in the output is accordingly monitored, i.e., whether it follows the setpoint reduction or not, and the pressure drop is compensated for by the second directional control slide, so that no negative effects are exerted on the actuating drive. Subsequently, a corresponding setpoint reduction and monitoring of the associated pressure in the hydraulic output can be effected using the second directional slide valve, wherein a pressure reduction compensation is produced by the first directional slide valve.

Advantageously, possible particle deposits in the hydraulic section can be washed away by the setpoint actuation and thus by a slight movement of the actuator of the actuating drive.

When two or three position detection devices are provided, which each generate a position actual value as a function of the detected position of the actuator, a 2-from-1, a 3-from-1, or a 3-from-2 evaluation can be provided, so that the two directional slide valves can also be operated when one or both of the position actual values fails, i.e. when one of the two or three position detection devices or two of the three position detection devices no longer operates as intended or when the signal transmission is disturbed.

By taking the corresponding preset values into account as substitute values, in particular also by the selection of 1 from 2, 1 from 3 or 2 from 3, the two directional control valves can also be operated in the event of a failure of the setpoint value presetting.

Advantageously, based on the self-test function shown above, the extended function of the actuator control unit can be simply switched off in the event of a fault, and the actuator control unit always also has the extended function according to fig. 1, so that additional risks of faults are avoided.

According to one embodiment of the invention, a plurality of electronic switching devices are provided, which are individually switchable in order to replace the position setpoint value or the position actual value.

At least one switching device or several switching devices can be implemented, for example, as a relay, in particular as a redundant relay.

As shown, it is also advantageous if at least two or three position detection devices are provided for generating the position actual values in each case as a function of the position of the actuator.

The two or three position detection devices are advantageously connected to at least two switching devices, so that a selection of 2-out-of-1 or 3-out-of-1 or a selection of 3-out-of-2 of the generated position actual values takes place. The actual position value of the switch device itself can be fed back to each switching device. Alternatively, only one of the two or three position actual values is fed back to all switching devices.

It is particularly advantageous if four electronic switching devices are provided, two of which are each connected to one of the position setpoint inputs of the respective directional or proportional valve and to the position controller and each have a default value input, and two of which are each connected to the position controller of the respective directional or proportional valve and to the respective position detection device and each have a default value input. Thus, the two position actual values fed back to the position regulators of the two directional slide valves or of the proportional valves can be replaced by preset values, and, in addition, the two position setpoint values fed back from the pilot system to the position setpoint input of the two directional slide valves or of the proportional valves can be replaced by corresponding preset values.

According to an embodiment of the invention, at least one or each switching device is provided with a switching input via which the respective switching device can be switched by providing a signal, in particular a preset current value, in order to replace the position actual value or the position setpoint value by the preset value.

In addition to the actuator control, the valve control device according to the invention comprises a hydraulically operable actuator and an actuator. The hydraulic actuating drive can have, for example, a pressure chamber which is connected to a pressure selection device for applying hydraulic pressure to the pressure chamber depending on the position of the two directional slide valves or proportional valves. In this case, the actuator can be operated with the hydraulic pressure in the pressure chamber against the force of a pretensioning spring of the hydraulic actuating drive.

According to an embodiment of the invention, some or all of the aforementioned components of the actuator control are integrated in a common assembly, which is switchable between the pilot system and the electrohydraulic proportional valve. According to a further embodiment, at least a part of the adjustment drive controller is integrated into the guidance system. It is also possible that at least a part of the actuator control is integrated into the control of the engine or work machine, with which the valve or other component of the engine or work machine is operated.

The invention shall be described in the following by way of example according to an embodiment and fig. 2.

In fig. 2, corresponding components already shown in fig. 1 are denoted by the same reference numerals. The actuator 1 with the actuator 1.1 is shown in detail, which in particular operates the valve 28 of the engine or work machine in its mass flow supply. Here, a steam turbine 29 is shown by way of example, which is supplied with live steam, the mass flow of which is regulated by means of a valve 28. The steam turbine 29 drives, for example, a compressor or an electric generator. The snap action valve 31 can be in particular upstream of the valve 28. However, instead of the steam turbine 29, a further engine or work machine may be provided.

The directional control valve module has two electrohydraulic proportional valves 2, 3, which are referred to as directional control valves in the present exemplary embodiment, and which, due to their design, convert the electrical signal or the current intensity or the current voltage into a hydraulic pressure which is supplied to the pressure chamber 1.2 of the actuating drive 1 in order to displace the actuator 1.1 more or less against the force of the pretensioning spring 1.3. For this purpose, the directional control valves 2, 3 have

electrical inputs

4, 5 and

hydraulic outputs

6, 7, respectively. The

hydraulic outputs

6, 7 are connected to a pressure selection device 8, which in turn delivers a common input pressure to the pressure chamber 1.2 as a function of the hydraulic pressure at the

hydraulic outputs

6, 7.

Thus, although the invention is shown in the present case with respect to a control drive with two directional slide valves, instead of directional slide valves, other electrohydraulic proportional valves 2, 3 can also be provided. Furthermore, the control device according to the invention can also be used to control a hydraulic actuating drive in which only an electrohydraulic proportional valve is provided.

The directional control valve module has a

position setpoint

9, 10 for each directional control valve 2, 3, which is connected to the

electrical input

4, 5 of the respective directional control valve 2, 3. In this connection, a

position controller

14, 15 is provided for each directional slide 2, 3, to which position controller the actual position value is also supplied in addition to the setpoint position value. As long as the position actual value is not replaced by the preset value, it comes from one of the position detection devices 11, 12, which detects the position of the actuator 1.1 of the actuating drive and generates a corresponding position actual value. Furthermore, a third position detection device 13 is provided, which likewise generates a position actual value as a function of the position of the actuator 1.1 of the actuating drive and feeds it back to the logic device of the directional control valve module for further processing. According to a further embodiment, the position actual values of all three

position detection devices

11, 12, 13 are first processed, so that one of the position actual values or an average value of the position actual values is selected as appropriate, in particular in the logic of the directional control valve module, and is supplied to all

position controllers

14, 15.

In addition to the actual position value of the third position detection device 13, the measured hydraulic pressure can be supplied, for example, from each

hydraulic output

6, 7 of the two directional control valves 2, 3 to a logic device, as is shown in fig. 2. The values supplied to the logic device may be present as analog values or, according to another embodiment, also as digital values.

Four

electronic switching devices

16, 17, 18, 19 are provided. The first electronic switching device 16 has a position actual value input 32 for the position actual value of the first position detection device 11, and furthermore has a default value input 22 and a position actual value output 34. The actual position value output 34 is connected to the position controller 14 of the first directional slide 2. As shown, a selection of 1 from 2 or 1 from 3 or 2 from 3 of the position actual values of all

position detection devices

11, 12, 13 is alternatively carried out and one or more selected position actual values are supplied to the first electronic switching device 16.

The second electronic switching device 17 has a position actual value input 33, to which the position actual value from the second position detection device 12 is applied and which is connected to the second position detection device 12. The second switching device 17 furthermore has a default value input 23 and a position actual value output 35. The actual position value output 35 is connected to the position controller 15 of the second directional control valve 3. Here, this also applies to the selection of 1 out of 2 or to the selection of 1 out of 3 or 2 out of 3, as mentioned for the first direction slide 2.

The third electronic switching device 18 is connected on the input side to the position setpoint input 9 and on the output side to the position controller 14 of the first directional slide 2. Furthermore, the third electronic switching device has a default value input 20. As long as a fault situation is not determined, the default value input 20 is connected to the position controller 14 in order to control the first directional slide valve 2 with a changed position setpoint value instead of the position setpoint value applied to the setpoint value input 9. Only when a fault situation is detected is the position setpoint input 9 connected directly to the output of the third electronic switching device 18 and supplied as setpoint to the first directional slide valve 2.

The fourth electronic switching device 19 likewise has a default input 21 and is connected on the input side to the position setpoint input 10 and on the output side to the position controller 15 of the second directional slide 3. In this case, as long as a fault situation is not determined, a preset value is supplied from the preset value input to the position controller 15 of the second directional slide 3. In the event of a fault, the setpoint value of the position setpoint input 10 is instead supplied to the position controller 15 of the second directional slide valve 3.

The functions described for the third and fourth electronic switching devices 18, 19 (i.e. the default value input is connected to the output as long as a fault situation is not determined and the position setpoint input is connected to the output when a fault situation is determined) can also be used in the first and/or second

electronic switching devices

16, 17. Accordingly, either the position actual value inputs 32, 33 (fault-determining) are connected to the position actual value outputs 34, 35, or the default value inputs 22, 23 (fault-not-determining) are connected to the position actual value outputs 34, 35.

A 2-from-1, 3-from-1 or 3-from-2 selection can also be provided in the external setpoint value.

Each switching

device

16, 17, 18, 19 has a switching input 24, by means of which it can be switched by applying a signal or a voltage or a current intensity, in order to replace the actual or set position value on the input side by a preset value on a

preset value input

20, 21, 22, 23, so that in the switching state, the preset value of the preset value input is applied to the output side of the

switching device

16, 17, 18, 19 and supplied to the

respective position controller

14, 15. Although a hardware solution with relays, for example, is shown here, the

switching devices

16, 17, 18, 19 can also be implemented in software.

As is indicated by the dashed lines, a large number of signals and/or pressures can be fed back into the electronic control device or control logic of the directional control valve module for further processing of the directional control valve.

Although this is not shown in fig. 2, a pressure supply, in particular with a pump and a hydraulic tank, can be provided similarly to fig. 1 in order to provide the necessary hydraulic pressure for the directional control valves 2, 3.

With the control device or the control drive controller according to the invention and the method according to the invention, the position setpoint value preset from the outside (in this case, for example, the guide system 30) can be replaced by a preset value corresponding to the changed position setpoint value in order to carry out the setpoint value control according to the invention, in order to avoid a too long standstill, and in order to improve the response speed of the system, or in order to carry out a functional test as shown.

Claims

1. A method for controlling a hydraulic actuating drive (1) having an actuator (1.1), the position of which is adjusted using an electrohydraulic proportional valve (2, 3) having at least one electrical input (4, 5) and at least one hydraulic output (6, 7), having the following steps:

1.1 detecting the position of the actuator (1.1) and generating a position actual value therefrom;

1.2 presetting a position setpoint value as a function of a preset for a desired position of the actuator (1.1) and adjusting a setpoint/actual value difference using the at least one electrohydraulic proportional valve (2, 3) such that the actuator (1.1) assumes a position corresponding to the position setpoint value;

1.3, the position setpoint value is also changed without changing a preset value for a desired position of the actuator (1.1);

wherein the hydraulic actuating drive (1) has at least two electrohydraulic proportional valves (2, 3) each having at least one electrical input (4, 5) and at least one hydraulic output (6, 7), and the hydraulic outputs (6, 7) of the electrohydraulic proportional valves are connected together for controlling the actuating drive (1) with a common hydraulic input pressure;

it is characterized in that the preparation method is characterized in that,

in the actuation of the position setpoint value supplied to one of the electrohydraulic proportional valves (2, 3), a pressure change in the hydraulic outputs (6, 7) of the electrohydraulic proportional valves (2, 3) is compensated by a pressure change in the hydraulic outputs (6, 7) thereof, which is regulated by at least one further electrohydraulic proportional valve (2, 3), in order to keep the common hydraulic input pressure to the regulating drive (1) constant.

2. Method according to claim 1, characterized in that the change of the position setpoint value takes place in the form of a regular or irregular superposition of vibrations on the setpoint value, which setpoint value is preset in accordance with a preset for the desired position of the actuator (1.1).

3. Method according to claim 1, characterized in that the change of the position setpoint value takes place in the form of a separate amplification and/or reduction of the setpoint value, which is preset in accordance with a preset for the desired position of the actuator (1.1).

4. Method according to claim 2 or 3, characterized in that in addition to the setpoint value change, the function of the electrohydraulic proportional valves (2, 3) and the function of further components for control are also tested, i.e. the setpoint value supplied to the electrohydraulic proportional valves (2, 3) is in turn reduced in a targeted manner and a corresponding change in the pressure in the respective hydraulic outputs (6, 7) is monitored.

5. Method according to claim 4, characterized in that in the test, the pressure decrease in the hydraulic outputs (6, 7) is compensated by a regulated pressure increase in the further hydraulic outputs (6, 7) in order to keep the common hydraulic input pressure for the regulating drive (1) constant.

6. Method according to claim 1, characterized in that the pressures in the hydraulic outputs (6, 7) are equalized again after compensation by changing the pressure in the further hydraulic outputs (6, 7).

7. A method according to claim 2 or 3, characterized in that the change of the position rating is disconnectable.

8. The method of claim 5, wherein the test is severable.

9. Method according to claim 1, characterized in that the position of the actuator (1.1) is detected with two or three position detection devices (11, 12, 13) and that a selection of 2-out-of-1, 3-out-of-1 or 3-out-of-2 is carried out from the position actual values generated by the position detection devices (11, 12, 13), wherein one or more selected position actual values are taken into account for the adjustment.

10. A control device for controlling at least one electrohydraulic proportional valve (2, 3) for controlling a hydraulic actuator drive (1) comprising an actuator (1.1), wherein the control device has an input and an output for at least one position actual value and a position setpoint value for the position of the actuator (1.1) and is set up for carrying out the method according to one of claims 1 to 9.

11. A control drive for controlling a hydraulic control drive (1) having an actuator (1.1);

having at least two redundantly arranged electrohydraulic proportional valves (2, 3) for generating a hydraulic input pressure for the actuating drive (1); wherein

Each electrohydraulic proportional valve (2, 3) has at least one electrical input (4, 5) and at least one hydraulic output (6, 7); and

the hydraulic outputs (6, 7) of at least two electrohydraulic proportional valves (2, 3) are connected together via a common hydraulic pressure selection device (8) for controlling the actuator (1) with a common input pressure;

having a position setpoint input (9, 10) for each electrohydraulic proportional valve (2, 3), which is connected to the electrical input (4, 5) of the respective electrohydraulic proportional valve (2, 3);

having at least one position detection device (11, 12, 13) for detecting the position of an actuator (1.1) of the actuating drive (1); wherein

The position acquisition device (11, 12, 13) generates a position actual value; and

each electrohydraulic proportional valve (2, 3) comprises a position controller (14, 15) which is designed to control a setpoint/actual value difference using a position setpoint value from the position setpoint value input (9, 10) and a position actual value from the position detection device (11, 12, 13);

at least one electronic switching device (16, 17, 18, 19) is provided, by means of which at least one position setpoint from the position setpoint input (9, 10) can be selectively replaced by a preset value;

it is characterized in that the preparation method is characterized in that,

the electronic switching device can also be used to selectively replace the actual position values from the position detection devices (11, 12, 13) by preset values.

12. Actuator control according to claim 11, characterized in that a plurality of electronic switching devices (16, 17, 18, 19) are provided, which are individually switchable in order to replace the position setpoint value or the position actual value.

13. Actuator control according to claim 11 or 12, characterized in that at least two or three position detection devices (11, 12, 13) are provided for generating a position actual value depending on the position of the actuator (1.1), respectively.

14. Actuator control according to claim 13, characterized in that the two or three position detection devices (11, 12, 13) are connected to at least two switching devices (16, 17, 18, 19) in such a way that a first position actual value is fed back to the first switching device (16), a second position actual value is fed back to the second switching device (17), and in the event of a failure of at least one of the two further position actual values, a third position actual value is fed back as a reserve position actual value, or in that a selection of 2-out-of-1, 3-out-of-1 or 3-out-of-2 is made from the position actual values of the two or three position detection devices (11, 12, 13), and a selected position actual value or a plurality of selected position actual values is fed back to both switching devices (16, 17).

15. The actuator control according to claim 12, characterized in that four electronic switching devices (16, 17, 18, 19) are provided, two of the electronic switching devices (18, 19) being connected to one of the position setpoint inputs (9, 10) of the respective electrohydraulic proportional valve (2, 3) and to the position controller (14, 15) and furthermore having a respective default value input (20, 21), and two of the electronic switching devices (16, 17) being connected to the position controller (14, 15) of the respective electrohydraulic proportional valve (2, 3) and to the respective position detection device (11, 12) and furthermore having a respective default value input (22, 23).

16. The control unit according to claim 11, characterized in that at least one switching device (16, 17, 18, 19) or each switching device (16, 17, 18, 19) has a switching input (24) via which the switching device can be switched by providing a signal for replacing a position actual value or a position setpoint value by a preset value.

17. The adjustment drive controller according to claim 11, characterized in that the pressure selection means (8) is embodied as a maximum pressure selection means.

18. Valve control device with a hydraulic actuator drive (1) comprising a hydraulically operable actuator (1.1) and an actuator drive controller according to any one of claims 11 to 17.

19. Valve control apparatus according to claim 18, characterized in that the hydraulic adjustment drive (1) has a pressure chamber (1.2) which is connected to the pressure selection device (8) for loading the pressure chamber with hydraulic pressure depending on the position of the two electro-hydraulic proportional valves (2, 3).

20. Valve control apparatus according to claim 19, characterized in that the actuator (1.1) can be operated with the hydraulic pressure in the pressure chamber (1.2) against the force of a pretension spring (1.3).